1. Technical Field
The present invention relates to gas filling apparatuses and, more particularly, to a gas filling apparatus for filling a gas into a storage apparatus for storing a semiconductor element or a reticle.
2. Description of Related Art
In the rapidly developing semiconductor technology, optical lithography plays an important role and wherever pattern definition is conducted, optical lithography is requisite. As to the application of optical lithography relating to semiconductors, a designed circuit pattern is used to produce a light-transparent reticle with a particular shape. Basing on the principle of exposure, after a light passes through the reticle to project on a silicon wafer, the circuit pattern formed on the reticle can be exposed onto the silicon wafer. Since any dust (such as particles, powders or an organic matter) can adversely affect the quality of such projected pattern, the reticle used to produce the pattern is required with absolute cleanness. Also, the silicon wafers and semiconductor elements also need to be absolutely clean. Thus, clean rooms are typically employed in general wafer processes for preventing particles in the air from defiling reticles and wafers. However, absolute dustless environment is inaccessible even in the known clean rooms.
Hence, storage apparatuses that facilitate protecting reticles and semiconductor elements from defilement are implemented in current semiconductor processes for the purpose of storage and transportation of reticles and semiconductor elements so as to ensure cleanness of the reticles and the semiconductor elements. When such storage apparatuses accommodate reticles and semiconductor elements in semiconductor processes, the reticles and the semiconductor elements can be isolated from the atmosphere when being transferred and conveyed between stations, so as to be secured from defilement caused by impurities that induces deterioration. Further, in advanced semiconductor factories, the cleanliness of the storage apparatuses is required to meet the Standard Mechanical Interface (SMIF), namely superior to Class 1. One solution for achieving the required cleanliness is to fill gas into the storage apparatuses. In the known technology, an external gas filling apparatus is connected with the storage apparatus so as to allow a gas to be filled into the storage apparatus through the gas filling apparatus.
The conventional gas filling apparatuses of all gas-filling types or means require an airtight device, which is typically an “o-ring seal”, equipped at a port where the gas is filled into the storage apparatus, as shown in U.S. Pat. Nos. 5,879,458, 6,042,651, 6,221,163, and 6,368,411, for preventing the gas from overflowing, which waste can burden the manufacturing costs. For achieving the airtightness between the port and the storage apparatus, the airtight device is most preferably formed as a soft plastic component for its flexibility and adjustability that secure the gas against overflowing due to the misalliance between the port and the storage apparatus. However, while the conventional airtight device is provided as a separate component, additional fastening components are required to fix it, or alternatively, an additional site is needed to receive such airtight device and additional fastening components. Furthermore, the consumable character of the soft plastic material can not only increase the costs for preparing spare parts and replacing components, but also generate contamination such as chippings and particles. Besides, though the airtight device made of soft plastic materials can be adjusted due to its flexibility, once the complete surface contact between an air entrance of the storage apparatus and the port fails, gas overflowing can still happen and in turn cause increased costs. Moreover, the volatile material that the soft plastic material tends to release continuously is yet another contaminant source.
Seeing that, the inventor of the present invention provides a gas filling apparatus having a port formed with a cambered receiving part to improve the current technology.